1. Field of the Invention
This invention relates in general to devices for transferring longitudinaly-moving rod-like cylindrical objects in a transverse direction, notably from a linear conveyor to a drum-like conveyor, as currently used in the manufacture of cigarettes.
2. Description of the Prior Art
Hitherto known modern cigarette-making machines are designed for manufacturing an endless rectilinear roll of tobacco wrapped in a sheet of paper, this roll being cut into sections of equal length which are subsequently caused to travel longitudinally by forming a line of cigarettes joined in end-to-end relationship on a conveyor.
The cigarettes are then introduced into a transfer device generally referred to as a transfer conveyor, which carries along the cigarettes separately in a direction perpendicular to their longitudinal axis while slowing down and eventually stopping their longitudinal movement.
In most cases the conveyor consists of a grooved drum rotatably driven at a constant speed about an axis parallel to the axis along which the roll of cigarettes is fed.
Each groove formed in the drum is of substantially semi-cylindrical configuration with a diameter or width of 9 to 10 mm, which flares out considerably at its cigarette-receiving or input end to enable the cigarettes to penetrate into the drum along more than half the cigarette length before engaging one wall of the groove which imparts a sudden shock to the cigarette in a direction across its axis.
The pitch between the successive grooves of the drum increases with the width of the inlet outflared portion, and the peripheral speed of the drum is proportional to the groove pitch. Therefore, the greater the pitch, the stronger the transverse shock applied to the cigarettes.
Before the cigarettes penetrate into the drum, their linear speed is increased considerably with respect to that of the roll, in order to reduce the time necessary for such introduction so that the width of the outflared portion of the groove can be increased to twice the diameter of the semi-cylindrical portion thereof.
However, in modern high-speed cigarette making machines operating at a rate of the order of 4,000 cigarettes per minute, the cigarettes are exposed to a treatment rather detrimental to their quality; in fact, the high-speed shock applied by the side wall of the groove to the cigarette causes the tobacco contained in the cigarette ends to escape partially therefrom and also a distortion of the cigarette proper; besides, the sudden braking of the cigarettes, of which the velocity of translation was increased by the preceding acceleration, is attended by the emptying of the front or leading end of the cigarette.
To avoid this inconvenience, a known proposition consisted in imparting a transverse movement to the cigarettes preliminary to their introduction into the drum, in order to approach as much as possible the peripheral speed of the drum. This action is attended by a twofold improvement: on the one hand, it is no more necessary to apply a substantial longitudinal acceleration to the cigarettes for speeding up their introduction into the drum grooves, and it is only necessary to increase their linear speed by 3 to 5% for developing a gap of 2 to 3 mm between the cigarettes in order to separate them and therefore avoid any frictional contact therebetween during the transverse movement of the leading cigarette; on the other hand, the pitch of the drum grooves may be selected to correspond substantially to the cigarette diameter, thus decreasing appreciably the peripheral speed of the drum.
Under these conditions, the transverse and longitudinal forces applied to the cigarettes are reduced considerably, this eliminating to a substantial degree the damages and distortions of the processed cigarettes.